Suspension system for one-wheeled vehicle

ABSTRACT

A self-propelled, one-wheeled vehicle may include a suspension system configured to provide arcuate, generally vertical motion of a board relative to an axle of a central wheel assembly when the vehicle encounters obstacles and bumps on a riding surface. Illustrative suspension systems may include a shock absorber and a swingarm that couple the wheel assembly to the board.

CROSS-REFERENCES

This application claims the benefit under 35 U.S.C. § 119(e) of thepriority of U.S. Provisional Patent Application Ser. No. 62/406,691,filed Oct. 11, 2016, the entirety of which is hereby incorporated byreference for all purposes. The following related applications andmaterials are incorporated herein, in their entireties, for allpurposes: U.S. Pat. Nos. 9,101,817; 9,452,345; U.S. patent applicationSer. No. 14/934,024; U.S. patent application Ser. No. 15/063,071.

FIELD

This disclosure relates to systems and methods for isolating aone-wheeled vehicle frame from certain effects of uneven terrain. Morespecifically, the disclosed embodiments relate to suspension systems forone-wheeled vehicles.

SUMMARY

The present disclosure provides systems, apparatuses, and methodsrelating to suspension systems for self-propelled one-wheeled vehicles.In some embodiments, a shock absorbing, self-balancing electricskateboard may include a board including first and second deck portionseach configured to receive a left or right foot of a rider orientedgenerally perpendicular to a direction of travel of the board; a wheelassembly including exactly one rotatable wheel disposed between andextending above the first and second deck portions; a motor assemblyconfigured to rotate the wheel around an axle to propel the skateboard;at least one sensor configured to measure orientation information of theboard; a motor controller configured to receive orientation informationmeasured by the sensor and to cause the motor assembly to propel theskateboard based on the orientation information; a compressible shockabsorber; a first linkage assembly connecting a first end of the shockabsorber to the board; and a second linkage assembly connecting a secondend of the shock absorber to the wheel; wherein at least one member ofone of the linkage assemblies is rotatable on an axis extendingperpendicular to the direction of travel of the board, and whereincompression of the shock absorber is configured to allow the board tomove relative to the wheel in response to bumps encountered by thewheel.

In some examples, a self-balancing electric vehicle may include a boarddefining a riding plane and including first and second deck portionseach configured to receive a left or right foot of a rider orientedgenerally perpendicular to a direction of travel of the board; at leastone rotatable wheel disposed between the first and second deck portions,and extending above and below the board; a hub motor configured torotate the wheel to propel the vehicle; at least one sensor configuredto measure orientation information of the board; a motor controllerconfigured to receive orientation information measured by the sensor andto cause the hub motor to propel the skateboard based on the orientationinformation; a compressible shock absorber; and a linkage assemblyoperatively connecting one end of the shock absorber to the board andanother end of the shock absorber to the wheel, wherein compression ofthe shock absorber is configured to allow arcuate, generally verticalmotion of the at least one wheel relative to the riding plane as thewheel encounters obstacles.

In some examples, a self-balancing electric vehicle may include a boarddefining a riding plane and configured to receive left and right feet ofa rider oriented generally perpendicular to a direction of travel of theboard; at least one rotatable wheel disposed between and extending aboveand below the board; a motor configured to rotate the wheel around anaxis of rotation to propel the vehicle; at least one sensor configuredto measure orientation information of the board; a motor controllerconfigured to receive orientation information measured by the sensor andto cause the motor to propel the skateboard based on the orientationinformation; and a linkage assembly linking the wheel to the board, thelinkage assembly including: first and second extension arms, eachrotatably attached to a respective lateral side of the wheel; aconnecting member rigidly interconnecting the extension arms; a shockabsorber having a first end coupled to the connecting member; and afirst coupling member joining a second end of the shock absorber to theboard; wherein the linkage assembly is configured to allow the ridingplane of the board to move in an arcuate, generally vertical directionrelative to the axis of rotation of the at least one wheel, in responseto bumps encountered by the wheel.

Features, functions, and advantages may be achieved independently invarious embodiments of the present disclosure, or may be combined in yetother embodiments, further details of which can be seen with referenceto the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric oblique view of an illustrative one-wheeledvehicle having a suspension system in accordance with aspects of thepresent disclosure.

FIG. 2 is another isometric oblique view of the vehicle of FIG. 1.

FIG. 3 is an overhead plan view of the vehicle of FIG. 1.

FIG. 4 is a first isometric oblique view of selected elements associatedwith illustrative suspension systems disclosed herein, showingrelationships between various components.

FIG. 5 is a second isometric oblique view of the selected elements ofFIG. 4.

FIG. 6 is a side elevation view of the vehicle of FIG. 1 with thesuspension system in a first state of compression.

FIG. 7 is a side elevation view of the vehicle of FIG. 1 with thesuspension system in a second state of compression.

FIG. 8 is a side elevation view of the vehicle of FIG. 1 with thesuspension system in a third state of compression.

FIG. 9 is an isometric partial view of another illustrative vehiclehaving a suspension according to the present teachings.

FIG. 10 is a side elevation partial view of the vehicle and suspensionof FIG. 10.

FIG. 11 is a schematic diagram depicting illustrative onboard controlsand electronic components suitable for use with vehicles in accordancewith aspects of the present disclosure.

DESCRIPTION

Various aspects and examples of swingarm suspension systems forone-wheeled vehicles, as well as related methods, are described belowand illustrated in the associated drawings. Unless otherwise specified,a one-wheeled vehicle having a swingarm suspension system, and/or itsvarious components may, but are not required to, contain at least one ofthe structure, components, functionality, and/or variations described,illustrated, and/or incorporated herein. Furthermore, unlessspecifically excluded, the process steps, structures, components,functionalities, and/or variations described, illustrated, and/orincorporated herein in connection with the present teachings may beincluded in other similar devices and methods, including beinginterchangeable between disclosed embodiments. The following descriptionof various examples is merely illustrative in nature and is in no wayintended to limit the disclosure, its application, or uses.Additionally, the advantages provided by the examples and embodimentsdescribed below are illustrative in nature and not all examples andembodiments provide the same advantages or the same degree ofadvantages.

Definitions

The following definitions apply herein, unless otherwise indicated.

“Substantially” means to be essentially conforming to the particulardimension, range, shape, or other aspect modified by the term, such thata feature or component need not conform exactly. For example, a“substantially cylindrical” object means that the object resembles acylinder, but may have one or more deviations from a true cylinder.

“Comprising,” “including,” and “having” (and conjugations thereof) areused interchangeably to mean including but not necessarily limited to,and are open-ended terms not intended to exclude additional, unrecitedelements or method steps.

Terms such as “first”, “second”, and “third” are used to distinguish oridentify various members of a group, or the like, and are not intendedto show serial or numerical limitation.

“Coupled” means connected, either permanently or releasably, whetherdirectly or indirectly through intervening components.

Overview

In general, and as shown in FIGS. 1-3, suspension systems according tothe present teachings may be suitable for one-wheeled electric vehicles,such as vehicle 10. Vehicle 10 is a one-wheeled, self-stabilizingskateboard substantially similar in its non-suspension aspects to theelectric vehicles described in U.S. Pat. No. 9,101,817 (the '817patent), the entirety of which is hereby incorporated herein for allpurposes. Accordingly, vehicle 10 includes a board 12 defining a ridingplane and having a frame 14 supporting a first deck portion 16 and asecond deck portion 18 (collectively referred to as the foot deck). Eachdeck portion 16, 18 is configured to receive a left or right foot of arider oriented generally perpendicular to a direction of travel of theboard, said direction of travel generally indicated at 20.

Vehicle 10 also includes a wheel assembly 22. Wheel assembly 22 includesa rotatable ground-contacting element 24 (e.g., a tire, wheel, orcontinuous track) disposed between and extending above the first andsecond deck portions 16, 18, and a hub motor 26 configured to rotateground-contacting element 24 to propel the vehicle. As shown in FIG. 1,vehicle 10 may include exactly one ground-contacting element. In someexamples, vehicle 10 may include two wheels disposed side by side andsharing a common axis of rotation.

As described in the '817 patent, vehicle 10 includes at least one sensorconfigured to measure orientation information of the board, and a motorcontroller configured to receive orientation information measured by thesensor and to cause hub motor 26 to propel the skateboard based on theorientation information.

Frame 14 may include any suitable structure configured to rigidlysupport the deck portions and to be coupled to an axle of the wheelassembly, such that the weight of a rider may be supported on tiltableboard 12 having a fulcrum at the wheel assembly axle. Frame 14 mayinclude one or more frame members, such as frame members 28 and 30, onwhich deck portions 16 and 18 may be mounted, and which may furthersupport additional elements and features of the vehicle, such as acharging port, end bumpers, lighting assemblies, battery and electricalsystems, electronics, controllers, and the like (not shown).

Deck portions 16 and 18 may include any suitable structures configuredto support the feet of a rider, such as non-skid surfaces, as well asvehicle-control features, such as a rider detection system 32.Illustrative deck portions, including other suitable rider detectionsystems, are described in the '817 patent, as well as in U.S. Pat. No.9,452,345, the entirety of which is hereby included herein for allpurposes.

A shaft 34 of hub motor 26 is coupled to frame 14 by a suspension system36, as shown in FIGS. 1-3. Suspension system 36 is a swingarm-typesuspension having a swingarm 38 damped by a damper or shock absorber 40.Various aspects and examples relating to system 36 are described ingreater detail below.

Examples, Components, and Alternatives

The following sections describe selected aspects of exemplary suspensionsystems for one-wheeled vehicles, as well as related systems and/ormethods. The examples in these sections are intended for illustrationand should not be interpreted as limiting the entire scope of thepresent disclosure. Each section may include one or more distinctinventions, and/or contextual or related information, function, and/orstructure.

A. Illustrative Swingarm Suspension

With reference to FIGS. 1-8, this section describes suspension system 36in greater detail.

FIGS. 1 and 2 are oblique isometric views of vehicle 10 and suspensionsystem 36. FIG. 3 is an overhead plan view of vehicle 10 and suspensionsystem 36. FIG. 4 is an oblique isometric view of suspension system 36and axle/shaft 34, isolated from remaining components to showrelationships between the various elements. FIG. 5 is an isometric viewof suspension system 36, isolated from vehicle 10. FIGS. 6-8 are sideelevation views of vehicle 10 and suspension system 36 in threerespective states of compression, showing how the suspension systemresponds.

Suspension system 36 includes swingarm 38 and shock absorber 40, asmentioned above. Swingarm 38 is a substantially U-shaped structurehaving a pair of rigid, spaced-apart, elongate extension arms 42 and 44.Arms 42 and 44 extend longitudinally from a transverse, pivotingcross-member 46 (also referred to as a connecting member) to straddlewheel assembly 22 and tire 24.

More specifically, the respective distal ends of arms 42 and 44 arecoupled to opposing ends of axle 34. For example, as shown in FIG. 4 andelsewhere, an end portion of arm 42 is attached (e.g., bolted) to afirst axle mounting member 48, and an end portion of arm 44 is attached(e.g., bolted) to a second axle mounting member 50. Axle mountingmembers 48 and 50 may be referred to as axle mounts. Axle mounts 48 and50 are rotatably or pivotably coupled to respective ends of axle 34,such that swingarm 38 can pivot with respect to the axle. In thisexample, axle mount 48 is pivotably coupled to the axle, e.g., using oneor more bearings or the like. Axle mount 50 is pivotably coupled to anintermediate structure in the form of a torque arm 52. Torque arm 52 isnon-rotatably coupled to an end of axle 34 (see below). An aperture ofaxle mount 50 fits over an axial protrusion 54 of torque arm 52.

At the proximal ends of arms 42 and 44, swingarm 38 is mounted tovehicle 10 by a pair of vertical frame mounting plates 56 and 58.Mounting plates 56 and 58 are affixed (e.g., bolted) to frame members 28and 30 of board 12, and are configured to pivotably retain end portionsof cross member 46. Frame mounting plates 56 and 58 (also referred to asplate members or coupling members) may include any suitable structureconfigured to couple suspension system 36 to board 12. In some examples,frame mounting plates 56 and 58 may be unitary with frame 14 and/or deckportion 16 and/or 18. In this example, mounting plates 56 and 58 aresubstantially planar, rigid plates bolted to the frame. Frame mountingplates 56 and 58 may provide additional mounting locations for otherelements of suspension system 36, as described below.

Accordingly, swingarm 38 is pivotable at one end with respect to axle 34and is pivotable at the other end with respect to board 12 and frame 14.This pivotable arrangement facilitates a swinging, generally verticalmovement of wheel assembly 22. In other words, the wheel and tire canmove up and down with respect to the board, through an arc correspondingto a radius defined by extension arms 42 and 44 (i.e., arcuate motion,also referred to as arcuately vertical).

However, this motion of the wheel is generally only desirable inresponse to a need, such as when riding the vehicle over a bump in theroad or on uneven terrain. Furthermore, the motion should be controlledor damped to allow for rider control and comfort. Accordingly,suspension system 36 includes shock absorber 40, which is pivotablycoupled to mounting plate 56 at a first end 60 and to the swingarm at asecond end 62. Shock absorber 40 may include any suitable dampingdevice. In this example, shock absorber 40 includes an air shockabsorber, such as the mountain bike shock absorber sold under the brandname FOX FLOAT DPS. Damping characteristics of the shock may beadjustable or selectable. In some examples, the shock may include alockout feature.

To offset and/or limit twisting of wheel assembly 22 and to ensure axle34 (and the stator of motor 26 affixed thereto) does not spin withrespect to frame 14 when power is applied to motor 26, torque arm 52 isconnected between axle 34 and mounting plate 58 by a torque link 64.Torque link 64 may include any suitable rigid link, the length of whichmay be securably adjustable. Link 64 is pivotably connected at a firstend 66 to mounting plate 58 and at a second end 68 by a ball joint 70 totorque arm 52.

As mentioned above, torque arm 52 is fixed to an end of axle 34, suchthat axle 34 cannot rotate with respect to the torque arm. In thisexample, axle 34 is keyed to torque arm 52 by a slot joint 72, visiblein FIG. 5. Specifically, a squared off end portion of the axle fits intoa channel 74 in torque arm 52, and the two are fastened together by anaxial bolt. The channel prevents any relative rotation between the twocomponents. Connecting another end of the torque arm directly to themounting plate using torque link 64 generally holds the axle in aconstant rotational orientation with respect to the frame of the vehicleas the wheel assembly moves up and down. As a consequence, the stator ofthe hub motor (which is affixed to the axle) is also held stationary(i.e., in a non-rotating state). Torque arm 52 and torque link 64 may bereferred to as a pair of strut members forming a strut assembly.

As shown in the drawings, first ends 60 and 66 of the shock absorber andtorque link, respectively, are spaced above frame 14 and cross member46. Second ends 62 and 68 are spaced from axle 34, but are generallylower than the first ends when the system is not compressed (e.g.,during steady-state operation).

Accordingly, system 36 includes two linkage assemblies, one at each endof shock absorber 40. Specifically, a first linkage assembly (e.g.,mounting plates 56, 58) connects first end 60 of shock absorber 40 toboard 12, and a second linkage assembly (e.g., swingarm 38) connectssecond end 62 of shock absorber 40 to wheel assembly 22. As describedabove, at least one member of one of the linkage assemblies isrotatable, and compression of the shock absorber allows the board tomove relative to the wheel in response to bumps encountered by thewheel.

In some examples, swingarm 38 may connect the second end of the shockabsorber to exactly one lateral side of the wheel. In some examples,swingarm 38 may comprise a dual-sided swingarm assembly that operativelyconnects the second end of the shock absorber to both lateral sides ofthe wheel. The first linkage assembly may be non-rotatably attached tothe board, and rotatably attached to the shock absorber. The firstlinkage assembly may be attached to the board at two separated positionson one lateral side of the board. The first linkage assembly may beattached to the board at two separated positions on each lateral side ofthe board.

In some examples, the first linkage assembly includes first plate member56 rigidly attached to a first side of board 12 and rotatably attachedto first end 60 of shock absorber 40, second plate member 58 rigidlyattached to a second side of board 12, and connecting member 46 joiningthe first and second plate members and rotatably attached to each of thefirst and second plate members.

In some examples, the second linkage assembly includes the strutassembly (e.g., torque link 64 and torque arm 52), such that the firststrut member (i.e., torque link 64) has one end rotatably attached tosecond plate member 58 and another end rotatably attached to the secondstrut member (i.e., torque arm 52). The second strut member has one endnon-rotatably attached to the wheel and another end rotatably attachedto link 64. Accordingly, the first and second strut members arecollectively configured (a) to allow the first linkage assembly to movesymmetrically on each lateral side of the board, with respect to a planedefined by the board, and/or (b) to impede spinning of axle 34 withrespect to frame 14 of board 12.

System 36 may include a linkage assembly linking the wheel to the board,where the linkage assembly includes first and second axial members(e.g., extension arms 42 and 44), each rotatably attached to arespective lateral side of the wheel. A connecting member (e.g.,cross-member 46) rigidly interconnects the axial members. Shock absorber40 has one end (e.g., end 62) coupled to the connecting member. At leastone coupling member joins the other end of the shock absorber (e.g., end60) to the board. The linkage assembly is configured to allow the ridingplane of the board to move relative to the axis of rotation of thewheel, in response to bumps encountered by the wheel.

Turning to FIGS. 6-8, vehicle 10 is shown with suspension system 36unloaded, partially compressed, and fully compressed, respectively.These conditions or states correspond to three different support surfacelevels, indicated at 76, 78, and 80. As shown in the drawings, as wheelassembly 22 is displaced upward, the distal ends of arms 42 and 44 ofswingarm 38 (i.e., the ends proximate axle 34) are displaced upward aswell. This compresses shock absorber 40, shortening the overall lengthof the shock. Because the shock absorber is designed to oppose suchaction, the resulting displacement of wheel assembly 22 is lesser inmagnitude and slower in speed than would otherwise be the case for agiven upward force. Shock absorber 40 may also bias the wheel to adefault or steady-state position relative to the frame 14. Accordingly,wheel assembly 22 may be urged downward after the upward force isreduced, thereby tending to maintain the tire in contact with thesupport surface.

In some examples, aspects of suspension system 36 may be described as aninverted slider crank linkage mechanism. Specifically, such a linkagemechanism comprises three pivot joints and one sliding (i.e., prismatic)joint. Here, the three pivots are (1) at the pivoting cross member 46,(2) at first end 60 of shock 40, and (3) at second end 62 of shock 40.Finally, the prismatic joint is formed by the lengthwise compressibilityof shock absorber 40 itself.

B. Illustrative Mono-Shock/Bell Crank Suspension

As shown in FIGS. 9 and 10, this section describes another illustrativesuspension system 100 suitable for use with vehicles such as vehicle 10.Relevant aspects of an illustrative vehicle substantially similar tovehicle 10 are shown, and are labeled with primed reference numbers(e.g., vehicle 10′) for convenience. FIG. 9 is a partial isometric viewof vehicle 10′ and system 100. FIG. 10 is a partial side elevation viewof vehicle 10′, with a portion of the frame removed to better showsystem 100.

Suspension system 100 includes a shock absorber 102, which may besubstantially similar to shock absorber 40 described above. Shockabsorber 102 is pivotably coupled at a first end 104 to a cross-member106 of a swing arm 108. The shock is coupled to a connection point onthe cross-member at or near a midpoint of the cross-member, such thatthe shock absorber is centrally aligned with vehicle 10′ and is disposedunder (below) one of the deck portions of vehicle 10′.

In this example, swing arm 108 is directly coupled at a distal end 116to axle 34′ of wheel assembly 22′. Cross member 106 may be furtherconnected to a pair of first links 110 on either side of the shockabsorber, which are connected at their other ends to a second link 112.Second link 112 is further pivotably coupled to a second end 114 ofshock absorber 102, and to the foot platform and/or frame 14′ via apivot pin 118 (or the like), as shown in the drawings.

Accordingly, upward force on wheel assembly 22′ will cause a distal(axle) end 116 of swingarm 108 to pivot upward. This pivoting pullsfirst links 110 toward the axle and compresses shock 102. Releasing orunloading the wheel will have the reverse effect.

C. Illustrative Control System

FIG. 11 shows a block diagram of various illustrative electricalcomponents of vehicle 10 (or 10′), including onboard controls, some orall of which may be included in vehicle 10 (or 10′). The electricalcomponents may include a power supply management system 300, a directcurrent to direct current (DC/DC) converter 304, a brushless directcurrent (BLDC) drive logic 306, a power stage 310, one or more 3-axisaccelerometer 314, one or more hall sensors 318, and/or a motortemperature sensor 322. DC/DC converter 304, BLDC drive logic 306, andpower stage 310 may be included in and/or connected to a motorcontroller 254. Accelerometer(s) 314 may be included in sensors 270.

Active balancing (or self-stabilization) of the electric vehicle may beachieved through the use of a feedback control loop or mechanism. Thefeedback control mechanism may include sensors 270, which may beelectrically coupled to and/or included in motor controller 254.Preferably, the feedback control mechanism includes aProportional-Integral-Derivative (PID) control scheme using one or moregyros (e.g., gyro(s) 280) and one or more accelerometers (e.g.,accelerometer(s) 314). Gyro 280 may be configured to measure a pivotingof the foot deck about its pitch axis. Gyro 280 and accelerometer 314may be collectively configured to estimate (or measure, or sense) a leanangle of board 12, such as an orientation of the foot deck about thepitch, roll and/or yaw axes. In some embodiments, the gyro andaccelerometer 314 may be collectively configured to sense orientationinformation sufficient to estimate the lean angle of frame 14 includingpivotation about the pitch, roll and/or yaw axes.

As mentioned above, orientation information of board 12 may be measured(or sensed) by gyro 280 and accelerometer 314. The respectivemeasurements (or sense signals) from gyro 280 and accelerometer 314 maybe combined using a complementary or Kalman filter to estimate a leanangle of board 12 (e.g., pivoting of board 12 about the pitch, roll,and/or yaw axes, with pivoting about the pitch axis corresponding to apitch angle (about axle 34), pivoting about the roll axis correspondingto a roll or heel-toe angle, and pivoting about the yaw axiscorresponding to a side-to-side yaw angle) while filtering out theimpacts of bumps, road texture and disturbances due to steering inputs.For example, gyro 280 and accelerometer 314 may be connected tomicrocontroller 269, which may be configured to correspondingly measuremovement of board 12 about and along the pitch, roll, and yaw axes.

Alternatively, the electronic vehicle may include any suitable sensorand feedback control loop configured to self-stabilize a vehicle, suchas a 1-axis gyro configured to measure pivotation of the board about thepitch axis, a 1-axis accelerometer configured to measure a gravityvector, and/or any other suitable feedback control loop, such as aclosed-loop transfer function. Additional accelerometer and gyro axesmay allow improved performance and functionality, such as detecting ifthe board has rolled over on its side or if the rider is making a turn.

The feedback control loop may be configured to drive motor 26 to reducean angle of board 12 with respect to the ground. For example, if a riderwere to angle board 12 downward, so that first deck portion 16 was‘lower’ than second deck portion 18 (e.g., if the rider pivoted board 12counterclockwise (CCW) about axle 34 in FIG. 1), then the feedback loopmay drive motor 26 to cause CCW rotation of tire 24 about the pitch axis(i.e., axle 34) and a clockwise force on board 12.

Thus, motion of the electric vehicle may be achieved by the riderleaning his or her weight toward a selected (e.g., “front”) foot.Similarly, deceleration may be achieved by the rider leaning toward theother (e.g., “back” foot). Regenerative braking can be used to slow thevehicle. Sustained operation may be achieved in either direction by therider maintaining their lean toward either selected foot.

As indicated in FIG. 11, microcontroller 269 may be configured to send asignal to BLDC drive logic 306, which may communicate informationrelating to the orientation and motion of board 12. BLDC drive logic 306may then interpret the signal and communicate with power stage 310 todrive motor 144 accordingly. Hall sensors 318 may send a signal to theBLDC drive logic to provide feedback regarding a substantiallyinstantaneous rotational rate of the rotor of motor 26. Motortemperature sensor 322 may be configured to measure a temperature ofmotor 26 and send this measured temperature to logic 306. Logic 306 maylimit an amount of power supplied to motor 26 based on the measuredtemperature of motor 26 to prevent motor 26 from overheating.

Certain modifications to the PID loop or other suitable feedback controlloop may be incorporated to improve performance and safety of theelectric vehicle. For example, integral windup may be prevented bylimiting a maximum integrator value, and an exponential function may beapplied to a pitch error angle (e.g., a measure or estimated pitch angleof board 12).

Alternatively or additionally, some embodiments may include neuralnetwork control, fuzzy control, genetic algorithm control, linearquadratic regulator control, state-dependent Riccati equation control,and/or other control algorithms. In some embodiments, absolute orrelative encoders may be incorporated to provide feedback on motorposition.

As mentioned above, during turning, the pitch angle can be modulated bythe heel-toe angle (e.g., pivoting of the board about the roll axis),which may improve performance and prevent a front inside edge of board12 from touching the ground. In some embodiments, the feedback loop maybe configured to increase, decrease, or otherwise modulate therotational rate of the tire if the board is pivoted about the rolland/or yaw axes. This modulation of the rotational rate of the tire mayexert an increased normal force between a portion of the board and therider, and may provide the rider with a sense of “carving” when turning,similar to the feel of carving a snowboard through snow or a surfboardthrough water.

Once the rider has suitably positioned themselves on the board, thecontrol loop may be configured to not activate until the rider moves theboard to a predetermined orientation. For example, an algorithm may beincorporated into the feedback control loop, such that the control loopis not active (e.g., does not drive the motor) until the rider usestheir weight to bring the board up to an approximately level orientation(e.g., 0 degree pitch angle). Once this predetermined orientation isdetected, the feedback control loop may be enabled (or activated) tobalance the electric vehicle and to facilitate a transition of theelectric vehicle from a stationary mode (or configuration, or state, ororientation) to a moving mode (or configuration, or state, ororientation).

With continued reference to FIG. 11, the various electrical componentsmay be configured to manage power supply 250. For example, power supplymanagement system 300 may be a battery management system configured toprotect batteries of power supply 250 from being overcharged,over-discharged, and/or short-circuited. System 300 may monitor batteryhealth, may monitor a state of charge in power supply 250, and/or mayincrease the safety of the vehicle. Power supply management system 300may be connected between a charge plug 268 of vehicle 10 and powersupply 250. The rider (or other user) may couple a charger to plug 268and re-charge power supply 250 via system 300.

In operation, power switch 266 may be activated (e.g., by the rider).Activation of switch 266 may send a power-on signal to converter 304. Inresponse to the power-on signal, converter 304 may convert directcurrent from a first voltage level provided by power supply 250 to oneor more other voltage levels. The other voltage levels may be differentthan the first voltage level. Converter 304 may be connected to theother electrical components via one or more electrical connections toprovide these electrical components with suitable voltages.

Converter 304 (or other suitable circuitry) may transmit the power-onsignal to microcontroller 269. In response to the power-on signal,microcontroller may initialize sensors 270, and rider detection device262.

The electric vehicle may include one or more safety mechanisms, such aspower switch 266 and/or rider detection device 262 to ensure that therider is on the board before engaging the feedback control loop. In someembodiments, rider detection device 262 may be configured to determineif the rider's feet are disposed on the foot deck, and to send a signalcausing motor 144 to enter an active state when the rider's feet aredetermined to be disposed on the foot deck.

Rider detection device 262, an example of which is depicted as riderdetection system 32 in FIGS. 1-2, may include any suitable mechanism,structure, or apparatus for determining whether the rider is on theelectric vehicle. For example, device 262 may include one or moremechanical buttons, one or more capacitive sensors, one or moreinductive sensors, one or more optical switches, one or more forceresistive sensors, and/or one or more strain gauges. Rider detectiondevice 262 may be located on or under either or both of first and seconddeck portions 16, 18 (see FIGS. 1-2). In some examples, the one or moremechanical buttons or other devices may be pressed directly (e.g., if onthe deck portions), or indirectly (e.g., if under the deck portions), tosense whether the rider is on board 12. In some examples, the one ormore capacitive sensors and/or the one or more inductive sensors may belocated on or near a surface of either or both of the deck portions, andmay correspondingly detect whether the rider is on the board via achange in capacitance or a change in inductance. In some examples, theone or more optical switches may be located on or near the surface ofeither or both of the deck portions. The one or more optical switchesmay detect whether the rider is on the board based on an optical signal.In some examples, the one or more strain gauges may be configured tomeasure board or axle flex imparted by the rider's feet to detectwhether the rider is on the board. In some embodiments, device 262 mayinclude a hand-held “dead-man” switch.

If device 262 detects that the rider is suitably positioned on theelectric vehicle, then device 262 may send a rider-present signal tomicrocontroller 269. The rider-present signal may be the signal causingmotor 26 to enter the active state. In response to the rider-presentsignal (and/or the board being moved to the level orientation),microcontroller 269 may activate the feedback control loop for drivingmotor 144. For example, in response to the rider-present signal,microcontroller 269 may send board orientation information (ormeasurement data) from sensors 270 to logic 306 for powering motor 26via power stage 310.

In some embodiments, if device 262 detects that the rider is no longersuitably positioned or present on the electric vehicle, device 262 maysend a rider-not-present signal to microcontroller 269. In response tothe rider-not-present signal, circuitry of vehicle 10 (e.g.,microcontroller 269, logic 306, and/or power stage 310) may beconfigured to reduce a rotational rate of the rotor relative to thestator to bring vehicle 10 to a stop. For example, the electric coils ofthe rotor may be selectively powered to reduce the rotational rate ofthe rotor. In some embodiments, in response to the rider-not-presentsignal, the circuitry may be configured to energize the electric coilswith a relatively strong and/or substantially continuously constantvoltage, to lock the rotor relative to the stator, to prevent the rotorfrom rotating relative to the stator, and/or to bring the rotor to asudden stop.

In some embodiments, the vehicle may be configured to actively drivemotor 26 even though the rider may not be present on the vehicle (e.g.,temporarily), which may allow the rider to perform various tricks. Forexample, device 262 may be configured to delay sending therider-not-present signal to the microcontroller for a predeterminedduration of time, and/or the microcontroller may be configured to delaysending the signal to logic 306 to cut power to the motor for apredetermined duration of time.

D. Selected Embodiments and Claim Concepts

This section describes additional aspects and features of suspensionsystems for one-wheeled vehicles, presented without limitation as aseries of paragraphs, some or all of which may be alphanumericallydesignated for clarity and efficiency. Each of these paragraphs can becombined with one or more other paragraphs, and/or with disclosure fromelsewhere in this application, including materials listed in theCross-References, in any suitable manner. Some of the paragraphs belowmay expressly refer to and further limit other paragraphs, providingwithout limitation examples of some of the suitable combinations.

Z0. An electric vehicle, comprising:

a board including first and second deck portions each configured toreceive a left or right foot of a rider oriented generally perpendicularto a longitudinal axis of the board;

a wheel assembly including a ground-contacting element disposed betweenand extending above the first and second deck portions;

a motor assembly mounted to the wheel assembly and configured to rotatethe ground-contacting element around an axle to propel the electricvehicle;

at least one orientation sensor configured to measure orientationinformation of the board;

a motor controller configured to receive board orientation informationmeasured by the orientation sensor and to cause the motor assembly topropel the electric vehicle based on the board orientation information;and

a suspension system including a shock absorber operatively coupled to aswingarm having a proximal end pivotably coupled to the board and adistal end coupled to the axle, such that the board is displaceablerelative to the axle along an arcuate, generally vertical path.

Z1. The vehicle of Z0, wherein the shock absorber is coupled to theswingarm and the board on a first side of the wheel assembly, thesuspension system further including a torque arm coupled to the axle andthe board on a second side of the wheel assembly.

A0. A shock absorbing, self-balancing electric skateboard, comprising:

a board including first and second deck portions each configured toreceive a left or right foot of a rider oriented generally perpendicularto a direction of travel of the board;

a wheel assembly including exactly one rotatable wheel disposed betweenand extending above the first and second deck portions;

a motor assembly configured to rotate the wheel around an axle to propelthe skateboard;

at least one sensor configured to measure orientation information of theboard;

a motor controller configured to receive orientation informationmeasured by the sensor and to cause the motor assembly to propel theskateboard based on the orientation information;

a compressible shock absorber;

a first linkage assembly connecting a first end of the shock absorber tothe board; and

a second linkage assembly connecting a second end of the shock absorberto the wheel;

wherein at least one member of one of the linkage assemblies isrotatable on an axis extending perpendicular to the direction of travelof the board, and wherein compression of the shock absorber isconfigured to allow the board to move relative to the wheel in responseto bumps encountered by the wheel.

A1. The electric skateboard of A0, wherein the second linkage assemblyis a single-sided swingarm assembly that connects the second end of theshock absorber to exactly one lateral side of the wheel.

A2. The electric skateboard of any of paragraphs A0 through A1, whereinthe second linkage assembly is a dual-sided swingarm assembly thatoperatively connects the second end of the shock absorber to bothlateral sides of the wheel.

A3. The electric skateboard of any of paragraphs A0 through A2, whereinthe first linkage assembly is non-rotatably attached to the board, androtatably attached to the shock absorber.

A4. The electric skateboard of A3, wherein the first linkage assembly isattached to the board at two separated positions on one lateral side ofthe board.

A5. The electric skateboard of A4, wherein the first linkage assembly isattached to the board at two separated positions on each lateral side ofthe board.

A6. The electric skateboard of A5, wherein the first linkage assemblyincludes a first plate member rigidly attached to a first side of theboard and rotatably attached to the first end of the shock absorber, asecond plate member rigidly attached to a second side of the board, anda connecting member joining the first and second plate members androtatably attached to each of the first and second plate members.

A7. The electric skateboard of A6, wherein the first linkage assemblycomprises a strut assembly including first and second strut members, thefirst strut member having one end rotatably attached to the second platemember and another end rotatably attached to the second strut member,the second strut member having one end non-rotatably attached to thewheel and another end rotatably attached to the first strut member,wherein the first and second strut members are collectively configuredto allow the first linkage assembly to move symmetrically on eachlateral side of the board, with respect to a plane defined by the board.

A8. The electric skateboard of A6, wherein the first linkage assemblyincludes first and second strut members, the first strut member havingone end rotatably attached to the second plate member and another endrotatably attached to the second strut member, the second strut memberhaving one end non-rotatably attached to an axle of the wheel andanother end rotatably attached to the first strut member, wherein thefirst and second strut members are collectively configured to impedespinning of the axle relative to the board.

B0. A self-balancing electric vehicle, comprising:

a board defining a riding plane and including first and second deckportions each configured to receive a left or right foot of a rideroriented generally perpendicular to a direction of travel of the board;

at least one rotatable wheel disposed between the first and second deckportions, and extending above and below the board;

a hub motor configured to rotate the wheel to propel the vehicle;

at least one sensor configured to measure orientation information of theboard;

a motor controller configured to receive orientation informationmeasured by the sensor and to cause the hub motor to propel theskateboard based on the orientation information;

a compressible shock absorber; and

a linkage assembly operatively connecting one end of the shock absorberto the board and another end of the shock absorber to the wheel, whereincompression of the shock absorber is configured to allow arcuate,generally vertical motion of the at least one wheel relative to theriding plane as the wheel encounters obstacles.

B1. The electric vehicle of B0, wherein the at least one rotatable wheelincludes exactly one rotatable wheel.

B2. The electric vehicle of any of paragraphs B0 through B1, wherein theat least one rotatable wheel includes two wheels disposed side by sideand sharing a common axis of rotation.

B3. The electric vehicle of any of paragraphs B0 through B2, wherein thelinkage assembly is a single-sided swingarm assembly connecting theshock absorber to exactly one lateral side of the wheel.

B4. The electric vehicle of any of paragraphs B0 through B3, wherein thelinkage assembly is a dual-sided swingarm assembly connecting the shockabsorber to both lateral sides of the wheel.

C0. A self-balancing electric vehicle, comprising:

a board defining a riding plane and configured to receive left and rightfeet of a rider oriented generally perpendicular to a direction oftravel of the board;

at least one rotatable wheel disposed between and extending above andbelow the board;

a motor configured to rotate the wheel around an axis of rotation topropel the vehicle;

at least one sensor configured to measure orientation information of theboard;

a motor controller configured to receive orientation informationmeasured by the sensor and to cause the motor to propel the skateboardbased on the orientation information; and

a linkage assembly linking the wheel to the board, the linkage assemblyincluding:

-   -   first and second extension arms, each rotatably attached to a        respective lateral side of the wheel;    -   a connecting member rigidly interconnecting the extension arms;    -   a shock absorber having a first end coupled to the connecting        member; and    -   a first coupling member joining a second end of the shock        absorber to the board;

wherein the linkage assembly is configured to allow the riding plane ofthe board to move in an arcuate, generally vertical direction relativeto the axis of rotation of the at least one wheel, in response to bumpsencountered by the wheel.

C1. The electric vehicle of C0, wherein the linkage assembly furtherincludes a strut assembly having a first end affixed to an axle of thewheel, and the first coupling member joins the second end of the shockabsorber to a first lateral side of the board and a second couplingmember joins a second end of the strut assembly to a second lateral sideof the board.

C2. The electric vehicle of C1, wherein the strut assembly includesfirst and second strut members pivotably joined together.

C3. The electric vehicle of C1, wherein the first and second couplingmembers are parallel planar members each rigidly attached to arespective lateral side of the board.

C4. The electric vehicle of C3, wherein each coupling member is attachedto the board at two separated attachment points.

C5. The electric vehicle of any of paragraphs C0 through C4, wherein theat least one wheel includes two wheels sharing a common axis ofrotation.

CONCLUSION

The disclosure set forth above may encompass multiple distinct exampleswith independent utility. Although each of these has been disclosed inits preferred form(s), the specific embodiments thereof as disclosed andillustrated herein are not to be considered in a limiting sense, becausenumerous variations are possible. To the extent that section headingsare used within this disclosure, such headings are for organizationalpurposes only. The subject matter of the disclosure includes all noveland nonobvious combinations and subcombinations of the various elements,features, functions, and/or properties disclosed herein. The followingclaims particularly point out certain combinations and subcombinationsregarded as novel and nonobvious. Other combinations and subcombinationsof features, functions, elements, and/or properties may be claimed inapplications claiming priority from this or a related application. Suchclaims, whether broader, narrower, equal, or different in scope to theoriginal claims, also are regarded as included within the subject matterof the present disclosure.

What is claimed is:
 1. A method for absorbing shocks encountered by aself-balancing electric vehicle, the method comprising: rotating a wheelof a one-wheeled vehicle around an axle using a motor assembly, thevehicle including a board tiltable about a tilt axis orientedperpendicular to a direction of travel, wherein the vehicle isconfigured to receive left and right feet of a rider oriented generallyparallel to the tilt axis; measuring tilt orientation information of theboard using at least one sensor; based on the tilt orientationinformation, using a motor controller to cause the motor assembly topropel the vehicle; and compressing and expanding a shock absorber inresponse to the board moving relative to the axle as a result of wheelmovement during operation; wherein the shock absorber comprises a firstlinkage assembly connecting a first end of the shock absorber to theboard, and a second linkage assembly connecting a second end of theshock absorber to the wheel; and wherein at least one member of one ofthe linkage assemblies is rotatable on an axis extending perpendicularto the direction of travel of the board.
 2. The method of claim 1,wherein the second linkage assembly is a single-sided swingarm assemblythat connects the second end of the shock absorber to exactly onelateral side of the wheel.
 3. The method of claim 1, wherein the secondlinkage assembly is a dual-sided swingarm assembly that operativelyconnects the second end of the shock absorber to both lateral sides ofthe wheel.
 4. The method of claim 1, wherein the first linkage assemblyis non-rotatably attached to the board, and rotatably attached to theshock absorber.
 5. The method of claim 4, wherein the first linkageassembly is attached to the board at two separated positions on onelateral side of the board.
 6. The method of claim 5, wherein the firstlinkage assembly is attached to the board at two separated positions oneach lateral side of the board.
 7. The method of claim 6, wherein thefirst linkage assembly includes a first plate member rigidly attached toa first side of the board and rotatably attached to the first end of theshock absorber, a second plate member rigidly attached to a second sideof the board, and a connecting member joining the first and second platemembers and rotatably attached to each of the first and second platemembers.
 8. The method of claim 7, wherein the first linkage assemblycomprises a strut assembly including a pair of strut members, a firststrut member of the pair having one end rotatably attached to the secondplate member and another end rotatably attached to a second strut memberof the pair, the second strut member having one end non-rotatablyattached to the wheel and another end rotatably attached to the firststrut member.
 9. The method of claim 8, further comprising: causing thefirst linkage assembly to move symmetrically on each lateral side of theboard, with respect to a plane defined by the board, using the pair ofstrut members.
 10. The method of claim 8, further comprising: impedingspinning of the axle relative to the board, using the pair of strutmembers.
 11. A method for absorbing shocks encountered by aself-balancing electric vehicle, the method comprising: rotating a wheelof an electric vehicle around an axis of rotation using a motorassembly, the vehicle including a tiltable board, wherein the boarddefines a riding plane and is configured to receive left and right feetof a rider oriented generally parallel to the axis of rotation;measuring tilt orientation information of the board using at least onesensor; based on the tilt orientation information, using a motorcontroller to cause the motor assembly to propel the vehicle; and inresponse to bumps encountered by the wheel, allowing the riding plane ofthe board to move in an arcuate, generally vertical direction relativeto the axis of rotation of the wheel, using a linkage assembly linkingthe wheel to the board; wherein the linkage assembly includes: first andsecond extension arms, each rotatably attached to a respective lateralside of the wheel; a connecting member rigidly interconnecting theextension arms; a shock absorber having a first end coupled to theconnecting member; and a first coupling member joining a second end ofthe shock absorber to the board.
 12. The method of claim 11, wherein thelinkage assembly further includes a strut assembly having a first endaffixed to an axle of the wheel, and the first coupling member joins thesecond end of the shock absorber to a first lateral side of the boardand a second coupling member joins a second end of the strut assembly toa second lateral side of the board.
 13. The method of claim 12, whereinthe strut assembly includes first and second strut members pivotablyjoined together.
 14. The method of claim 12, wherein the first andsecond coupling members are parallel planar members each rigidlyattached to a respective lateral side of the board.
 15. The method ofclaim 14, wherein each coupling member is attached to the board at twoseparated attachment points.
 16. The method of claim 11, including twowheels sharing the axis of rotation.
 17. A method for absorbing shocksencountered by a self-balancing electric vehicle, the method comprising:rotating a wheel of a one-wheeled vehicle around an axle using a motorassembly, the vehicle including a board tiltable about a tilt axisoriented perpendicular to a direction of travel, wherein the boardincludes first and second deck portions each configured to receive aleft or a right foot of a rider; measuring tilt orientation informationof the board using at least one sensor; based on the tilt orientationinformation, using a motor controller to cause the motor assembly topropel the vehicle; and using a suspension system to absorb shocks whenthe board moves relative to the axle during operation; wherein thesuspension system includes a shock absorber operatively coupled to aswingarm having a proximal end pivotably coupled to the board and adistal end coupled to the axle, such that the board is displaceablerelative to the axle along an arcuate, generally vertical path; andwherein the shock absorber is coupled to the swingarm and the board on afirst side of the wheel, the suspension system further including atorque arm coupled to the axle and the board on a second side of thewheel.
 18. The method of claim 17, wherein the wheel comprises aground-contacting element extending above the first and second deckportions.
 19. The method of claim 17, further comprising: using thetorque arm to hold the axle in a constant rotational orientation withrespect to the board as the wheel moves up and down.
 20. The method ofclaim 19, wherein the torque arm is coupled to the board by a torquelink.